Proofing papers are designed to accurately reproduce colour in pre-press applications, with papers mimicking base colour, weight and gloss level. Proofing papers offer a wide colour gamut- typically exceeding the gamut capability of the final print paper. This allows for highly accurate proofing of the final copy, using a lower cost paper. Prints could be made on the final output media, but it comes down to cost, as to do this would be a much more expensive alternative.
The surface of proofing papers offers excellent short-term stability and fast ink drying. They are not intended for long term use.